Tribological behaviour of laser-clad TiC_p composite coating

The wear behaviour of laser-clad TiC-Ni alloy coatings was studied by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and pin-on-ring friction and wear tests. TiC particles can act as hard barriers to resist the scoring and plastic deformation of the matrix and then delay the occurrence of delamination without distinctly increasing the friction coefficient of the coatings. The degree of wear depends mainly on the extent of debonding and removal of TiC particles. With increasing normal load, mild scratching with fine grooves, oxidative wear with a thin layer of Ni₂O₃ film, delamination wear with serious plastic deformation and regular scale-like features were observed on the worn surfaces of coatings corresponding to various wear conditions. The softening and local melting of worn surface layers caused by friction heat produces a crushed crystalline or amorphous structure.